共查询到20条相似文献,搜索用时 250 毫秒
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将过氯乙烯(CPVC)作为渗透汽化膜材料,用于分离乙醇/水溶液,研究了膜对水和乙醇的吸附溶解性能,对乙醇/水溶液的分离性能,分离温度对膜分离性能的影响。发现过氯乙烯膜优先透水,对乙醇/水溶液选择性高而透量较小。膜的稳定性较好。 相似文献
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吸附树脂AB—8对甜菊甙的吸附性能及在其提取纯化中的应用 总被引:4,自引:0,他引:4
考察了大孔吸附树脂AB-8对甜菊甙的吸附性能,和溶液的HP值,洗脱剂的种类及流速对树脂吸附,脱附性能的影响,结果表明,AB-8树脂对甜菊甙吸附量高,循环使用性能好且易于洗脱。 相似文献
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分子结构对聚芳醚酮薄膜透气性的影响 总被引:1,自引:0,他引:1
分子结构对聚芳醚酮薄膜透气性的影响王忠刚,陈天禄,徐纪平(中国科学院长春应用化学研究所长春130022)关键词聚芳醚酮,气体分离膜,结构-性能关系为了改善聚合物薄膜的透气性能,开发具有高透气性和高选择性的膜材料,人们对膜分子结构与透气性能间的关系进行... 相似文献
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碳纤维原丝的性能好坏在很大程度上决定着碳纤维的最终性能。缺陷少、细旦化、高取向、高纯化等是高性能原丝的基本要求。其中原丝的取向度在很大程度上决定了碳纤维在预氧化、碳化过程中形成的类石墨片层的取向结构,这会影响碳纤维最终的强度和模量,所以制备出高取向的碳纤维原丝具有重大意义。本文聚焦于高取向碳纤维原丝制备工艺,首先分析了高取向原丝的重要性,然后在原丝制备工艺上将纺丝方法以及牵伸工艺对取向度的影响进行总结分析,同时介绍了微积分纳米层叠法和高取向复合纤维原丝的制备工艺,指出优质的初生纤维以及具有稳定化取向排列的原丝是制备高取向碳纤维原丝的关键,以期对提升原丝的取向度进而提升碳纤维性能的研究有所贡献。 相似文献
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环氧-丙烯酸酯混杂光固化体系的研究 总被引:9,自引:0,他引:9
研究环氧-丙烯酸酯混杂光固化体系中引发剂的协同作用,证实混杂光固化过程中自由基引发剂对阳离子引发剂二苯基碘Weng盐的增感作用,混杂光固化膜具有优良的机械性能,其抗冲击性能,抗弯曲性能及硬度优于单纯的阳离子体系固化膜,与自由基体系固化膜性能接近。混杂光固化膜的玻璃化转变温度高于自由基体系固化膜;它的耐溶剂性能优异,耐丙酮擦拭次数比自由基固化膜高25倍以上,比阳离子固化膜高3.5倍。这可能是由于混杂光固化过程中形成的IPN结构造成的,动态粘弹谱和扫描电镜的实验结果证实了这一结论。 相似文献
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稀土对玻璃纤维填充金属-塑料多层复合材料抗冲击磨损性能的影响 总被引:1,自引:1,他引:1
研究了稀土元素处理玻璃纤维填充金属-塑料多层复合材料在冲击载荷、干摩擦条件下的摩擦和磨损性能,并利用扫描电子显微镜(SEM)对磨损表面进行了观察和分析,结果表明,用稀土表面改性剂处理玻璃纤维表面,可以提高玻璃纤维与聚四氟乙烯之间的界面结合力,改善复合材料的界面性能,并有利于在偶件表面形成分布均匀、结合强度高的转移膜,使复合材料与偶件表面之间的对摩减轻,大幅度地降低了复合材料的磨损,从而使复合材料具有优良的摩擦性能和抗冲击磨损性能。 相似文献
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Winny Dong Jeffrey Sakamoto Bruce Dunn 《Journal of Sol-Gel Science and Technology》2003,26(1-3):641-644
The electrochemical properties of high surface area transition metal oxide aerogels are extremely interesting because aerogels serve to amplify surface effects. As a result, the electrochemical properties are dominated by surfaces rather than by bulk behavior. In the case of vanadium oxide aerogels this leads to extraordinary electrochemical properties, including an extremely high capacity for lithium and electrochemical responses that are both battery-like and capacitor-like. By exploiting sol-gel synthesis, it is possible to synthesize nanocomposite electrodes in which aerogels are in intimate contact with carbon nanotubes. The resulting nanocomposites exhibit superior electrochemical properties, especially at high discharge. 相似文献
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快淬NdFeB磁粉颗粒度对聚合物粘结NdFeB磁体永磁性能的影响 总被引:8,自引:0,他引:8
研究了快淬NdFeB永磁粉颗粒及其分布对聚合物粘结NdFeB永磁材料性能的影响。快淬Nd-FeB永磁粉颗凿大小及其分布显著地影响聚合物结NdFeB永磁材料的磁性能。适当尺寸的快淬NdFeB磁粉组合可获得高的结NdFeB永磁帝主要是由于快淬NdFeB磁粉硬度高,呈鳞片状,其尺雨越大越难获得高密度,但尺寸太小又将破坏磁粉的结构,导致磁性能恶化。 相似文献
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The incorporation of comonomers during ethylene polymerization can efficiently modulate important material properties of the polyolefins. Utilizing bioresourced comonomers for the generation of high‐performance polyolefin materials is attractive from a sustainability point of view. In this contribution, bioresourced eugenol and related comonomers were incorporated into polyolefins through palladium‐catalyzed copolymerization and terpolymerization reactions. Importantly, high‐molecular‐weight catechol‐functionalized polyolefins can be generated. The introduction of different metal ions induces efficient interactions with the incorporated catechol groups, leading to enhanced mechanical properties and self‐healing properties. Moreover, the catechol functionality can greatly improve other properties such as surface properties, adhesion properties, and compatibilizing properties. The catechol‐functionalized polyolefin was demonstrated as a versatile platform polymer for accessing various materials with dramatically different properties. 相似文献
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P. Srikari Tantri Anup K. Bhattacharya Sheela K. Ramasesha 《Journal of Chemical Sciences》2001,113(5-6):633-649
Molybdenum disilicide is a high temperature structural ceramic with many attractive properties for engineering applications.
Foremost amongst these is its stability in corrosive atmospheres up to about 1600°C. However, there are a few undesirable
properties that need to be addressed before it can become a viable material in high temperature applications. Since MoSi2 forms thermodynamically stable composites with both metals and ceramics, many reinforcing materials are incorporated into
the matrix to improve the fracture toughness and creep properties. The low temperature oxidation can be controlled by making
high density (> 95% of theoretical density) compacts. This article summarizes the important attempts that are made in improving
the properties of molybdenum disilicide-based ceramics by the reinforcement with other materials. 相似文献
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P. M. Korinek 《Macromolecular Symposia》1994,82(1):61-65
Poly(tetrafluoroethylene) (PTFE) already known since 50 years, Is a unique material among plastics due to its chemical inertness, heat resistance, electrical insulation properties and low coefficient of friction. Its high melt viscosity needs special ways of processing. That fact led to the development of melt-processible fluoropolymers such as Perfluoroethylene-propylene (FEP) and Perfluoroalkoxy (PFA). Now we have a third generation which is an amorphous fluorpolymer made by copolymerizing tetrafluoroethylene with 2,2-bis (trifluoromethyl) - 4,5 - difluoro -1,3 - dioxole. The bulky cyclic structure prevents the normal crystallisation as with PTFE polymers. The amorphous fluoropolymers have high clarity and dissolve in selected solvents. Having C-F, C-C and C-O bonds the well known properties as high temperature and chemical resistance are retained. Dielectric constant is in the range 1.83 - 1.93 up to 10.00 MHz the lowest of any plastic material. Optical properties are also very special. Refractive index is very low, in the range 1.29 - 1.32. Transmission is high from UV to IR and the polymer is not photo-degraded. The unique electrical and optical properties, coupled with high chemical and thermal stability, plus the ability to work from solution offers a powerful tool for those working on the frontiers of technology. 相似文献
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B. Venkatram C. Kailasanathan P. Seenikannan S. Paramasamy 《International Journal of Polymer Analysis and Characterization》2016,21(7):647-656
Composite materials, made by replacing traditional materials, are used because of their capability to produce tailor-made, desirable properties such as high tensile strength, low thermal expansion, and high strength to weight ratio. The need for the development of new materials is essential and growing day by day. The natural sisal/general polymer (GP) reinforced with nanoclay composites has become more attractive due to its high specific strength, light weight, and biodegradability. In this study, sisal–nanoclay composite is developed and its mechanical properties such as tensile strength, flexural strength, and impact strength are evaluated. The interfacial properties, internal cracks, and internal structure of the fractured surface are evaluated using scanning electron microscope. The thermal disintegration of composites are evaluated by thermogravimetric analysis. The results indicate that the incorporation of nanoclay in sisal fiber/GP can improve its properties and can be used as a substitute material for glass fiber-reinforced polymer composites. 相似文献
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由于小应变条件下,动态流变行为的测定不会对材料本身的结构造成影响或破坏,动态流变研究被认为是表征填充类聚合物体系填料颗粒的分散状态的有效方法[1~3].众所周知,窄分子量分布的均相聚合物体系在低频率(ω)区域的粘弹行为满足线性粘弹关系,而填充类聚合物基复合材料的流变行为表现出特殊的粘弹特征[4~8],即在低ω区域显示出非线性粘弹行为的特殊响应.特别是所谓的"第二平台(second plateau)"现象,被认为与体系形态结构密切相关[9]. 相似文献
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R. H. Baughman H. Gleiter N. Sendfeld 《Journal of Polymer Science.Polymer Physics》1975,13(10):1871-1879
The mechanical properties (Young's modulus, ultimate tensile strength, deformation processes) of extended-chain polydiacetylene crystals are investigated. The properties observed are similar to those of metal and ceramic whiskers. The elastic modulus is strain-dependent and the ultimate tensile strength increases with decreasing crystal size. The maximum tensile strength observed was 1700 Nmm?2. The ultimate tensile strength seems to be controlled by the presence of a small number of defects near the surface at which fracture nucleates. Irreversible deformation of the crystals was observed to occur by crack propagation normal and parallel to the direction of the macromolecules. The observed mechanical behavior corresponds to exceptionally high per-chain properties. The per-chain modulus obtained for these crystals is nearly as high as that of diamond. A chain-aligned polyethylene fiber with the same per-chain mechanical properties would have an ultimate strength as high as 0.9 × 104 Nmm?2. 相似文献